Most clinical chemistry analysis requires a separated blood sample. Separation of a usable sample from whole blood is traditionally achieved by centrifuging blood collection tubes for several minutes. The current practice is for tubes be spun for approximately 10 to 15 minutes at 1200 g.
The current method has several drawbacks, however. First, the blood separation time delays delivery of analytical results. Second, the long separation time requires large centrifuge batch sizes in order to maintain high sample throughput during blood processing. This necessitates the use of large, expensive centrifuges.
Rapid blood separation systems have been developed. For example, see U.S. Pat. Nos. 5,030,341 and 5,308,506 to McEwen et al. These patents describe specialized blood separation tubes and a specialized instrument for rotating the tubes about a longitudinal axis. U.S. Pat. Nos. 4,846,974 and 4,981,585 to Kelley et al. disclose disk-shaped cassettes for centrifugal separation of blood with a high speed rotary drive. All of the above systems require specialized blood collection or separation containers in addition to dedicated instruments, which add a continuing burden to the overall cost of the system.
What is needed is a blood separation system and method which is easy to use, contributes to the low cost operations of the laboratory, and rapidly provides a separated blood sample.